JPH01111514A - Variable damping force-type suspension controller - Google Patents

Abstract

PURPOSE:To favorable improve a suspension characteristic by judging a distinguished main oscillation mode over a whole vehicle according to a variation in the state quantity of each wheel suspension, and the like so as to compute its corresponding optimum target controlling force. CONSTITUTION:A state detection means I is provided which detects physical quantity affecting a suspension characteristic, state quantity showing suspension movement, and state quantity showing vehicle running state. According to its output, oscillation modes consisting of pitching, rolling, bouncing, and the like over a whole vehicle are computed respectively by a state judging means II01, so as to judge the distinguished main oscillation mode of them over a whole vehicle. According to the main oscillation mode, target controlling force is computed by a target controlling force computing means II02, and a deviation between the target controlling force and detection controlling force which has been computed to correspond to the physical quantity by a detection controlling force computing means II2 is computed by a deviation computing means II3. According to the deviation, an actuator means IV is driven via a driving means III so as to control a suspension characteristic.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a support device for a building or a traveling device,
The present invention relates to a vibration control device when vibration is generated due to external force or disturbance (road surface).

(Prior Art) The inventors of the present invention first proposed a method for reducing the consumption of a suspension of a vibrating body, with the aim of suppressing or damping vibration when vibration is caused by an external force or disturbance. Calculates the target control force to achieve the optimal state based on the change in state quantity due to the vibration of the vibrating body due to energy,
We have developed a device that controls the damping force of the suspension of the vibrating body to follow the target control force, improving the vibration characteristics and reducing the amount of vibration of the vibrating body (Japanese Patent Laid-Open No. 108319/1983).
(see publication).

As shown in Fig. 2, this vibration control device detects physical quantities that affect the characteristics of the suspension that supports the vibrating body, and also includes a state detection means (■) that indicates the movement of the suspension, a control means (■), and a control means (■). The driving means (■) power-amplifies the output signal of the power amplifying means (2), and the actuator means (2) continuously variably controls the characteristics of the suspension based on the output of the power amplifying means (2), and the control means (2) is the output of the state detection means (2). Target control force calculation means ■□ calculates the optimal target control force from physical quantities and state quantities, taking into account external forces or disturbances acting on the suspension, and state detection means ■
The detection control force calculation means (2) calculates the detected control force corresponding to the physical quantity detected by the suspension, and the deviation calculation means (2) calculates the deviation between the target control force and the detected control force. Since the suspension characteristics are continuously and variably controlled to equivalently generate a control force according to the difference between the considered target control force and the detected control force,
As a result, vibrations are suppressed by equivalently adding a target control force to the suspension.

This conventional vibration control device is capable of finely controlling physical quantities by taking external forces or disturbances into account, while also reducing energy consumption, simplifying the configuration, and reducing the weight, space, and cost of power sources, piping, etc. .

(Problems to be Solved by the Invention) In the conventional technology, a target control force is calculated independently for each support structure as the state of the vehicle suspension changes, and the control deviation between the calculated target control force and the control target value is calculated. A control signal is given based on the

Therefore, in a vehicle consisting of a multi-degree-of-freedom vibration system.

The problem was that it was not possible to set a target control force based on detection of the overall state of the vibrating body for coupled vibrations of various vibration modes.

In addition, the optimal target control force needs to be a control force that immediately responds to the most prominent vibration mode based on the amount of moment-to-moment changes in the state of the vehicle, which is the vibrating body, so it is necessary to have a state discrimination function. was there.

The present invention provides these.

(Means for solving the problem) The present invention is a state detection means! , control means■, drive means■,
The actuator means (2) is provided, and the control means (2) includes a state determining means (2) for determining the state of the vibration state of the vibrating body by comparing it with its main vibration state. , and target control force calculation means ■ based on the state determination means. 2, a detected control force calculation means (2), and a deviation calculation means (2) between the target control force and the detected control force.

That is, the state detection means (2) detects physical quantities that affect the characteristics of the suspension that supports the vehicle, and also detects state quantities that indicate the movement of the suspension and state quantities that indicate the running state of the vehicle.

The pitch, roll,
Condition determination means (■) that calculates each vibration mode consisting of a combination of bounces, etc., and determines the predominant main vibration mode of the entire vehicle among each vibration mode. , and state determination means ■
. Target control force calculation means that calculates the optimal target control force based on the main vibration mode of the entire vehicle determined by □■
. 2, a detection control force calculation means ■2 that calculates the detected control force corresponding to the physical quantity detected by the state detection means ■; and a deviation calculation means ■3 that calculates the deviation between the target control force and the detected control force.
It is equipped with the following.

The driving means (2) power-amplifies the deviation signal between the two control forces, which is the output of the control means (2).

Based on the power amplified output, the actuator means continuously adjusts the characteristics of the suspension in order to equivalently generate a control force corresponding to the deviation of the actual detected control force from the target control force that takes into account external forces or disturbances acting on the suspension. This is a variable control system.

Then, by using these means, the main vibration mode that is prominent in the entire vehicle is determined from the degree of change in the state quantity or physical quantity of the suspension of the entire vehicle and each axis, and the optimal target control force is calculated accordingly. It generates an optimal target control force that corresponds to the overall main vibration mode, and continuously optimally and variablely controls the characteristics of the suspension.

(Operations and Effects) In a suspension support device that constitutes a multi-degree-of-freedom vibration system, a vibrating body having at least two support structures produces achieved vibrations that are correlated to each vibration mode. In this device, an optimum gain is set for each rapid mode that occurs in the vibrating body, and vibration is controlled according to the main vibration mode. That is, the target control force calculation means (2). In the process of reaching step 2, state determination means ■. 1, the main vibration mode of the vibrating body is identified, and the state quantity is multiplied by the optimal feedback gain calculated in advance to calculate the optimal target control force.

This makes it possible to provide optimal control according to the main vibration mode of the vibrating body, and compared to controlling each vibration system alone, the vibration level can be reduced in accordance with the behavior of the vibrating body as a whole. Furthermore, it is possible to improve the adaptability of vibration reduction in response to state changes, and at the same time when the amount of vibration reaches a predetermined level or higher.

It is possible to increase the control amount of that vibration mode and quickly switch the control of the main vibration mode up to that point. Furthermore, since the necessary amount of control is added when necessary, the need to constantly use energy is reduced, and an energy-saving, compact, and inexpensive system can be constructed.

The principle of operation of the present invention as described above will be explained in more detail.

A time-series optimal target control force U that takes into account vibrations of the vibrating body caused by external forces or disturbances acting on the suspension that supports the sprung mass m when the vibrating body consists of a sprung mass and the sprung masses of four wheels like a vehicle. is calculated as follows, assuming active control.

A pitch-bounce rapid vibration model of a pitch-bounce control sprung mass m is assumed as shown in FIG. 3(a).

m 'Z = c t (Z tRZ i. J k□(
Zn+Zt. J+fzQ2CZrR-. R) L
(Zr++ Z-0ll)+f2(1-1)1”0=Q
t(QtCZttr-'ZtoR)+kt(Zts+
Zt. R)-f,)Q-(C2(Z-RZFOR)+
k2(Zraz,.R)-f2> (1-2) Here, for one front and rear wheel target control force U□ and u2.

Actual actuation force f1. Assume that f2 can approximate the characteristics of a first-order lag.

'f,=--! −f □+−”u,
(1-3)T f,=--! -f, +-! ”us
(1-4)T A 6-man power 2-output control optimal regulator is constructed based on equations (1) to (4). State variables are adopted for each of the front and rear wheels on the right side of the vehicle as follows.

Xl(j)=(yLtVtv)'zv)'z+
Lt fJ' (1-5) Here, the state space equation is: y2 = Zrl Zr0I1 Next, as shown in Figure 3 (a), the same equation is applied to the left front and rear wheels of the two sets of vehicles. Assuming a pitch bounce achievement vibration model, the suspension relative displacement is expressed as y4=ZrL-ZroL, and the state variables are taken for the left front and rear wheels of the vehicle as follows.

Xz(t)=0'iy M3t'/*e 3'41
f3+f4)” (1-9) Here, the state space equation is expressed by the following equation.

To explain in more detail, the state space equations (1-6) and (1-10) generally become as follows.

A pitch-bounce two-degree-of-freedom model with a sprung mass m is assumed as shown in FIG. 3(b).

m 2 = −c x (Z −之,.) klCZ
tZto)+f□02CZr-Zr. )-to 2(
Z, -Z,. )+f, (1-11)I”a=91
(at(之f-ne.)+、(Zt-Zt.)-f□)
Qr(Cz(Zr-Zr.)+,(Z,-Z,,)-
f, ) (1-12) Here, Z,=Z+(-m,)θ, Z,=Z+Q,θ
(1-13) 之, = 之+(L)b-之, ＝之+Q
7b(1-13') State variable V1=Zt Zloy
Let y2=Zr Zra.

Then, equations (1-1) and (1-2) become as follows.

-mu (so, . - rock.) e (1-15)"")'
z= Laz3't Cta"z)'z kxi
3)'z C2a'3y2+a2f, +a, f2-1
(Q side.+Q,''i,.)fig<'i,,.-'i,
,. (1-16) It is assumed that there is a first-order lag between the front wheel control operating force U□ and the operating force f1, and that there is also a first-order lag between the rear wheel control operating force U2 and the operating force f2.

"-" (i=1.2) ul l+T.

°ulJ L (1-17)f
1 =] Ni Ding Se 2 = Dan h - M (1-18) T (1-5), (1-6) and (1-7), (1
-8) Construct an optimal regulator for 6-manpower 2-output control based on formula.

The state space equation is written as follows.

x(t)=Ax(t)+Bu(t)+B'x(t)
(1-19) Variable conversion (Xzy Xzt Xst X** Xs+ X5) =
(yty 'ltr 3'21'/zt f, t
L), the state space equation becomes as follows.

The evaluation function J is J, = f [ρ, f, ′+ρ2f2”+q 2+q
z&”]dt”f-[ρzL”+ρzL”+x”(t)
Qx(t)cod t (1-22) where.

q, ka+q, bz='1tQr"+'1zx2z2(
q□ntQr−qz) q□Q,”+q2 □
+ x, X 4 + LX 4 From this, the Q□ matrix becomes as follows.

From this, 2 can be found for the optimal feedback gain.

Next, the roll/bounce mode will be explained.

Roll bounce control Assume a roll bounce model as shown in Figure 4.

m'Z=-cL (ZL-之,.) Lt, (ZLZt
a) + f LCa(Zll Z″8°)−La(Z
RZRO) + f R(2-1) ■. °ζ=QL(Q
L (ZL ZL.) + kLL (ZLZLO) one inch c (z, z, .) - (z, -z, o)] - tt) fl
Jc++ (ZB zll.) + kxi (Z++
ZRo) + fC (Z L Z c.) (ZRZR6
)]-f, ) (2-2) Here.

Z, = Zt(-Q L)ζ, ZII=z+6ζ
(2-3) ZL=Z+(-QL)ζ, No.8
= 之+raζ (2-3')ζ: Roll angle (fourth
(See Figure (b)) It is assumed that there is a first-order lag between the right wheel control operating force uL and the operating force fL, and between the right wheel control operating force U and the operating force fR.

M=-shi=(i=L,R) ul l+T1□? L=run-L ”r, 'r, (2-4)i
R = Force - T, T, (2-5) State variable'/x = ZL, ZLOI X2 = ZR - Zll
Let's set it as o.

Coefficient b1. b2. Set b3 as follows.

Variable transformation (xl, x2.x,, x4.x,, x,) = (y4.y
,,y2. C, fL, fll), the state space equation becomes as follows.

(2-1), (2-2), (2-4), (2-5
) formula, x1=x2(2-7) (Ls+bz+5I2L)xi clb mountain+b1x,
+b2x.

1...m-(raZ,.+QL″1R0)-9(Lo-2io)
(2-8) m-work
3x4+b2xs +b3xi1
... (QiZLa+Q,, so3゜)+h(so,.-shi,.'
) (2-10)m
I・I KL xs=-Kxs+,-TuL(2-11)・I
K, l x, = -ear x, +y; u poverty (2-1
2) From Equation 6 above, the state space equation is as follows.

The evaluation function J is assumed as follows.

J=f [ρtft,”+ρ2f,12+q,no2+
q2ξ”ldt (2-14) Therefore, q1=q2=
1, the Q matrix becomes the following equation.

From this, the optimal feedback gain sequence can be found.

Pitch/roll control Assume a pitch/roll model as shown in Figure 5.

I p'8 = Q trcp (zp zF.) + k
p(Zp Zp.)+fpc)-L(c++(Za-
Lo)-kR(Zi-Zllo)+fii) (3-1
)■. °ζ=ut(cp(之、-之、.)+kp(Z
p-z,. )? [(Zp Zpo) (ZI ZRo)
] fpt)F QJCa(Zi ZRo)+Lc4(ZRZRO)+
#[(ZFzpo) (za Zs+o)] fpJ
(3-2)R where, Zp=(L)θ+(OL)ζ, Zll=Q, 0
+ Q, lζ (3-3), = (-QI)b
+(-QL)ξ, starvation: Q −a + Q Rξ (3
-3') θ: pitch angle, ζ: roll angle (Fig. 5(b)
Reference) Left front axle control operating force uFL, operating force fFL, and right rear wheel control operating force u! Assume that there is a first-order lag between IR and the actuation force fllll+.

Gold 1. J(錇2.-±fFL ”L TFL (3-4)f
RR death -6, -Sat f3□ TRRTRII (3-5) State variable X1=Z, -Z,. F yz=Zi Zl
lo (3-6) Therefore, the state space equation becomes as follows.

(XttXzyX3+XntXstXs)=(y1*7
t+yz+7ztfp+, +fpR)X□=xz
(3-7)x2=(Q□k
p+I24)x, +Q, cpx2(42kR+I2.)
xa-Q2c,,x4-Q,x,+2. x,
(3-8)X3=X4
(3-9)X4=-(Q2 kp + 12s)
x, -Qz QpXz + Cnx km + L)X
i+Q3allx4+Q2xs-Q3x,
(3-10) I KFL (
3-11) 8゛2-Tile
(3-12) From the six equations above, consider the evaluation function J as follows: 6J=/[
ρx f FL” + ρ2f,, “+q a” + q2ξ”
]dt=f [ρtfpL2+/)af, li”+
X(t)'QiX(t)codt Q corresponding to the evaluation function J
The matrix is expressed by the following equation, assuming q1=qz=1.

On the other hand, the time-series optimal target control force U that takes into account the vibration of the vibrating body caused by an external force or disturbance acting on the suspension supporting the vibrating body m is based on the premise of active control, for example, the equation of motion in Fig. 6 is It becomes as follows.

m″x″=u(x, delusion, °x″) ・・・・・・・・・
・・・・・・・・・(4) However, X is suspension displacement due to external force or disturbance, x is suspension speed, °
x° is the acceleration given to the vibrating body. That is, the target control force U is a function of x, x, "x".

Here, if the target control force U is further expressed in a general form, it becomes linear.

U= Σg+X+ ・・・・・・・・・・・・
(5) Here, s g+ is a contribution gain coefficient for providing optimal vibration suppression, that is, 1 in the above state equation. K is a control gain corresponding to Usually included. Namely.

The optimal target control force U is the state physical quantity x of the vibrating body m.

is detected instantaneously, and the coefficient g is calculated based on the contribution of each
1, a so-called instantaneous state feedback control system is constructed, which can provide optimal vibration suppression to the essential mass vibration system.

With respect to this target control force U, a sensor detects a physical quantity f acting on the suspension, negative feedback is given to the physical quantity, and the output of the deviation E (= u - f) is power amplified by a driving means ■. The actuator means (2) attached to the suspension is driven to continuously control the physical quantity f. In other words, the optimal target control force u(x
By extracting the force related to the physical quantity f from , t' control, simplify configuration,
This reduces the weight, space, and cost of power sources, piping, etc.

Table 1 Next, state determination means (■) in the 9 controls. , explain the effect of . That is, it is necessary to detect the vibration state of a vehicle, which is a vibrating body, and select the main vibration state, that is, the predominant vibration mode.

State detection means! The vehicle consists of a sprung mass and four sprung masses, and consists of four displacement meters that detect the relative displacement between each sprung mass and the sprung mass. Relative displacement y□y of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel detected by the state detection means I 3'21
Based on y31 and y4, two sets of attitude angles φ4. φre
PLI PR+ and PR, calculate P Rz.

Further, based on the results of these two sets of state evaluation amount calculations, the state evaluation amount is obtained by finding the average value φ, PRt, PB of each of the two sets of values. By examining the magnitudes of these state evaluation quantities φt, P Rt, and P B t, it is possible to determine the magnitude of each vibration mode and determine the outstanding main vibration mode of the entire vehicle. FIG. 7 and Table 1 summarize the flow of calculations and evaluation amounts.

In addition, in Table 1, T.

Tr and L represent the front and rear wheelbases, ie, the tread, and the front and rear wheelbases, ie, the wheel base, respectively.

(Example) A specific example will be described in the case of an automobile in which an orifice 130 is disposed in the middle of an oil passage or pipe 150 that communicates between a hydraulic cylinder 110 and a gas-liquid fluid spring 120 as shown in FIG. 8(a). This is applied to a gas-liquid fluid suspension device. Here, wheel suspension will be representatively explained using FIGS. 8 to 11.

The vibration control device of this embodiment basically belongs to the embodiment shown in FIG. 1, and consists of a state detection means (2), a control means (2), a drive means (2), and an actuator means (2). The control means (■) is a state determination means (■). 1 and detection control force calculation means ■
2 and target control force calculation means■. 2, a deviation calculation means ■, and a sign adjustment means ■.

, and an integrating means ■.

As shown in FIG. 9, the state detection means (2) is a suspension arm 6 that rotatably supports the wheels of the suspension.
2 and the vehicle body frame 63 to detect relative displacement.

An amplifier 20 that is connected to the potentiometer 10 and outputs a signal representing the relative displacement y between the axle and the vehicle body when the vehicle is running; and a differentiator 30 that differentiates the relative displacement y output from the amplifier 20 to detect the relative speed i. .

A pressure sensor lla attached to the hydraulic cylinder 110 chamber to detect the acting wheel load, an amplifier 21a to detect the wheel load W from pressure, and an accumulator 12
A pressure sensor llb is attached to the entrance of the oil chamber of 0 to detect damping force, and an amplifier 21b is connected to the pressure sensor 11b and amplifies its output.

A differential amplifier 31 that detects the damping force fc as the difference between the output of the amplifier 21b and the output of the amplifier 21a, an acceleration sensor 12 that is attached to the vehicle body and detects acceleration, and an amplifier 22 that is connected to the acceleration sensor 12 and amplifies it. , an integrator 32a that integrates the output to detect the sprung mass velocity λ2, an integrator 32b that further integrates the output to detect the sprung mass displacement x2, and an integrator 32b that is attached to the gas chamber of the accumulator 120 to detect the sprung mass velocity λ2 the temperature sensor 13 that detects the temperature sensor, the amplifier 23 that is connected to the temperature sensor and amplifies the sensor output, the aforementioned vehicle speed sensor 14 that is attached to the output shaft of the automobile transmission and detects the vehicle speed V, the displacement sensor 56, and the displacement sensor 56. and an amplifier 24 that outputs a signal representing. The displacement sensor 56 detects the displacement of the spool 58 that continuously opens and closes the oil passage 150 to form a variable orifice in the actuator means (2) consisting of a linear actuator 55 and a valve body 59 as shown in FIG. 8(b). It is something to do.

Condition determination means ■. 1 is the vehicle speed V, the relative displacement of each axis V
C='jxt Vxp yat y4) p Wheel load W.

An input section 71 receives the gas temperature t, and based on the input, calculates the vehicle state quantities shown in Table 1 through the calculation processing shown in FIG. 7, determines the main vibration mode, and obtains the target control force. An arithmetic processing unit 72 that calculates the optimal gain, a storage unit 73 that stores the arithmetic method of the arithmetic processing unit 72, and
An output unit 74 that outputs the result of the arithmetic processing performed by the processing unit 72
The microcomputer 70 is composed of:

The functions performed by the microcomputer 70 will be explained in detail along the flowchart of FIG. The output of the vehicle speed sensor is taken in, and in order to detect the weight of the car body, which changes depending on the number of passengers or loaded cargo, that is, the sprung mass m of the air-liquid suspension, the force W acting on each wheel is read individually, and the load on each axis is calculated. The gas temperature signal for correction and the relative displacement y of each wing are read (step p z on the flowchart).

Next, each import relative displacement y* Yzr y3? y4Yo Each vehicle state quantity shown in Table 1 is calculated (P3). Also, a running judgment is made to determine whether the vehicle is in a running state (P
4) If the vehicle does not reach the running state, initialize the initial position of the damping valve (Ps).

Next, in P, , , P, , P, the vehicle state quantity is optimal for calculating the target control force u1 to u4 corresponding to each vibration mode based on the magnitude relationship from the judgment value of each vibration mode evaluation amount. Calculate the gain from 1□ to 16 (Ps).

On the other hand, if the evaluation amount of pitch roll, roll bounce, and pitch bounce vibration is not larger than the judgment value,
Replace the wheel suspension with a linear 21 degrees of freedom model in advance, assuming the active control suspension,
Using the linear square form optimal control method, relative displacement y, relative velocity n, sprung mass displacement x2. Sprung speed ÷ 2. Optimal gains G11 to G1. for damping force fc. is calculated and outputted from the output section 74 (P.).

In addition, if each vibration mode in steps P, ,P, ,P, is predominant, the mode-specific optimum gain of P is set to 6, ~, , (i = 1 to 4), and each of Plo is A coefficient is added for each state variable of the optimum gains Gl□ to G15 for each axis, and the final optimum gain is calculated (P□1).

Optimal target control force calculation means ■. 2 is the optimum gain 011~ outputted from the output section 74 of the microcomputer 70.
It consists of five multipliers 41 to 45 and an adder 50 for each axial muscle to calculate the optimum target control force U from G15 and the corresponding state signal according to the following equation.

In other words, the optimal target control force for wheels 1 to 4 is U-engineered? When u21 u3t u4, the following equation is obtained.

ut=(Gzx+KzJ)'+(Czu+Kxz)n+
Gz3"Xz+014・x, +(G,, 1/10g) fc
uz=(Gzt+KaJy+(Gzz+Kzz)n+G
z,'Xz+024・x,+(G2.+2.)fcu
a=(1a to G3L+)y+(Gaz+KtJ3'+G
si”Xz 十G34・Xz”(03s+KtJfeu4
=(G4z+Kza)y+(G4z+Kz4)y+G+
a'xz ten G44 x, + (G4s+,,) fc On the other hand, the sprung mass vibration model (bounce pitch.

pitch roll), it can be written as follows depending on how the symbols are taken.

u,=G, 1y +G, y + (1. to G13+.
) Xtz+ (G, + K 2) x, + (G,, +
) flcuz = Gz1'/ +022 V +
(G22 + Kzz) Xzz+(G24+K12)
Xzz+(Gzs+Kzs) f, cu3=G, □y
10G, 2y+ (G3.+, □)xB+ (G34 +
X23) X32 + (G3s + KIG) f
aCu4=G44 V +G423' + (G43
+ X41) X42+(G4++Kz4)X4z+
(G4s+Kzs)f4eThis will be described below as - boat fishing.

u=G□・y1G2・y103・x2 10G4・X2+05・fc ・・・・・・・・・
...(6) Deviation calculating means ■3 is target control force calculating means ■. Calculate the deviation ε between the detected control force (i.e., the damping force to be detected in the case of this embodiment) fc calculated by the detected control force calculation means 2 with respect to the optimal target control force U output from 2. It consists of a deviation device 51.

The sign adjustment means (2) consists of a multiplier 52 that multiplies the output ε of the deviation device 51 by the suspension relative speed n. When performing damping force control according to the deviation ε with respect to the target control force U, the multiplier 52 determines whether or not the deviation ε with respect to the target control force can be controlled by the damping force, and if it is controllable, It outputs a signal that determines the direction of increase or decrease in damping force, and
If the damping force is uncontrollable, the damping force is reduced and a signal that approaches zero is output.

The sign adjustment function of the 1 multiplier 52 will be explained using Table 2 and FIG. 8(a). When the target control force U is positive in the upward direction perpendicular to the vehicle body, and the relative speed i of the suspension is positive in the direction of contraction of the air-liquid suspension, both the target control force U and the relative speed i are the same. direction,
For example, when the piston of the hydraulic cylinder 110 moves upward (positive direction) and the target control force U also moves upward (positive direction), the oil in the hydraulic cylinder 110 passes through the orifice 130 in proportion to the relative speed. As it flows into the liquid fluid spring 120.

By changing the opening degree of the orifice 130 using a control signal, it is possible to change the pressure within the hydraulic cylinder 110, that is, the magnitude of the upward (positive direction) damping force fc of the damping coefficient. In this case, the output ε of the deviation device 51 is positive (u
> fc), the orifice opening is set in the closing direction and the damping coefficient is increased to increase the damping force, and when ε is negative (u(fc)), it is set in the open direction and the damping coefficient is made smaller to decrease the damping force. If the piston of the hydraulic cylinder 110 moves downward (negative direction) and the target control force U is also downward (negative direction), contrary to the above, the oil Gas-liquid fluid spring 120 to orifice 130
Since it flows into the hydraulic cylinder 110 through the
The magnitude of the damping force fc can be changed. In this case as well, when ε is positive (-u') -f c), the orifice opening is set in the open direction and the damping coefficient is made small to reduce the damping force, and when ε is negative (-u<fc), it is What is necessary is to output a control signal to set the suspension in the closing direction, increase the damping coefficient, and increase the damping force that equivalently acts on the suspension.

Therefore, when the target control force U and the suspension relative speed n are in the same direction, the damping force fc can be controlled based on the target control force U. On the other hand, the target control force U and the relative speed N are opposite, for example, the piston of the hydraulic cylinder 110 moves upward (positive direction), and the target control force U moves downward (negative direction).
In this case, the oil in the hydraulic cylinder 110 flows into the gas-liquid fluid spring 120 through the orifice 130, so if the orifice opening is kept at a certain opening (not controlled), the relative speed An upward (positive direction) damping force acts, and the damping force cannot be controlled based on the target control force U.

Therefore, if the orifice opening degree is fully opened by the control signal, the damping coefficient is minimized, and the damping force fc in the positive direction that equivalently acts on the suspension is reduced, it will be as if the damping force fc in the case of no control is controlled by the target control. This corresponds to applying a force in the direction of force U and reducing it. The output ε (= u − f c) of the deviation device 51 at this time is
Since the target control force U is negative and fc is in the same direction as the relative speed n, it is positive, so it is always negative.

Furthermore, even when the piston of the hydraulic cylinder 110 moves downward (negative direction) and the direction of the target control force U is upward (positive direction), the damping force is controlled based on the target control force U in the same way as above. Therefore, it is desirable to use a control signal to fully open the orifice and minimize the damping coefficient, thereby reducing the damping force equivalently acting on the suspension. At this time, the output ε(= u − f
c) is negative because the target control force U is positive and fc is in the same direction as the relative speed n, so it is always positive. Therefore, when the target control force U and the relative velocity are in opposite directions,
Since it is not possible to control the damping force based on the target control force U, it is sufficient to fully open the orifice and reduce the damping force using the control signal.

Table 2 As mentioned above, Table 2 summarizes the damping force and the control direction of the orifice opening degree with respect to the output ε of the deviation device 51 in each state. In order to basically achieve this logic, by multiplying the sign of ε by the sign of the suspension relative velocity which is in the same direction as the damping force, the output is a control signal corresponding to the control direction of the orifice opening. becomes. Here, it is sufficient that the control signal determines the direction of increase or decrease of the damping force, and in order to improve the noise ratio to the deviation ε signal with respect to the target control force, that is, the S/N ratio, the 1 multiplier 52 is used to directly compensate E. The sum of ε multiplied by the speed ton;
was used as the control signal.

Integrating means 5 consists of an integrator 53 consisting of an operational amplifier, a resistor R that determines the integral gain, and a capacitor C.
In order to eliminate the offset (residual deviation) of the deviation ε between the damping force fc and the target control force U by time-integrating the output εi of the multiplier 52, the damping force of the suspension is detected and fed back as an integral input. , from the viewpoint of control system responsiveness and stability, integral gain KK (=1/C
R) was set to KK=2400. In addition, to prevent the integrator from drifting, its output was fed back to the input via a resistor.

The drive means (2) comprises a drive circuit 54 which provides negative feedback of the spool displacement signal of the actuator means (2) to the output of the integrator 53 and outputs a current proportional to the deviation signal.

As shown in FIG. 8(b), the actuator means (2) is a hydraulic cylinder 110 of the gas-liquid fluid suspension attached to the suspension arm 62 and the vehicle body frame 63.
A valve body 59 is integrated with the valve body 59, an oil passage 150 that communicates the oil chamber of the accumulator 120 and the oil chamber of the hydraulic cylinder 110 through the valve body 59, and a variable orifice that is continuously opened and closed. a moving coil 57 of a linear actuator 55 that is integrated with the spool, a permanent magnet 60 that applies a force to the moving coil in response to the current that is the output of the drive circuit 54 that flows through the moving coil, and the linear actuator. It consists of a displacement sensor 56 which is attached to the moving coil 55 and detects the displacement of the spool in order to suppress the force acting on the moving coil, and an amplifier 24 which outputs a signal representing the displacement.

The movement of the spool with respect to fEydt, which is the time-integrated output εi of the multiplier 52 of the control means (2), which is the control input to the actuator means (2), will be explained using FIG. 11. In FIG. 11, the horizontal axis shows the control input ftydt, and the vertical axis shows the spool displacement X, the orifice opening degree a, and the damping coefficient C with respect to the spool displacement.

In order to ensure a comfortable ride when riding, control human power/1ydt
When is zero, the spool displacement signal is fed back to the drive circuit to maintain the spool displacement X at a neutral position (0%) and provide an orifice opening degree, that is, a damping coefficient C, that satisfies riding comfort.

The value of the damping coefficient C at that time is a function of the relative speed of the suspension. Next, the positive output of the multiplier 52 (+ε:
/), the control input is also positive (+/ε:/dt), so the spool displacement The orifice opening degree a is decreased, the damping coefficient C is increased, and the damping force is increased. Also, the negative output (−εn) of the multiplier 52
Since the control input is also negative (-fEydt) for
The spool displacement x1 is from the neutral position to the oil path 15 according to ε
0 in the fully open (x, = +100%) direction, the orifice opening degree a is increased, and the damping coefficient C is lowered to reduce the damping force.

The operation of this embodiment is as follows.

In response to external force or disturbance from the road surface, the microcomputer 70 detects the output V of the vehicle speed sensor 14, the axle load W detected by the amplifier 21a, the relative displacement y detected by the linear potentiometer, and the temperature sensor 13. Based on the gas temperature t, the relative displacement y.

Relative speed n, sprung mass displacement X2t sprung mass speed; c2. The optimal gains 01 to G for the damping force fc are output, and the above (
13) The adder 50 outputs the optimal target control force U calculated based on the formula. The deviation between the output of this target control force U and the damping force fc to be controlled is taken, and the deviation is multiplied by the relative speed using a multiplier 52 to convert it into a control signal for the damping force. Integrator 53. By applying current to the linear actuator 55 via the drive circuit 54 and moving the spool 58, the damping coefficient changes, and the damping force fc can be changed continuously.

Note that although the multiplier 52 is used in sign adjustment means (4) of the present invention, a divider may also be used.

Further, although the above embodiment is applied to a gas-liquid fluid suspension, the present invention may be embodied in a conventional coil suspension instead of a gas-liquid fluid suspension, and a coil spring may be used instead of a high-pressure gas spring. can.

The device according to the embodiment of the present invention having the above-described function detects the nonlinear spring constant kc of the gas-liquid fluid spring from time to time based on the relative displacement y and gas temperature t, identifies the main achieved vibration mode of the entire vehicle, and Since the target control force is calculated accordingly, instantaneous vehicle vibration can be immediately optimally controlled according to the main achieved vibration mode, and can be adapted to all driving conditions.As a result, ride comfort and This has the advantage that running stability and the like can be greatly improved.

Also, sign adjustment means■. The multiplier 52 uses the product ε of the deviation ε with respect to the target control force and the relative speed of the suspension to increase the signal level compared to the deviation ε, so the control signal has a good signal-to-noise ratio, that is, a good S/N ratio. εi is obtained.

Further, by an integrator 53 that integrates the signal over time.

The fluffy component of sprung mass vibration that affects riding comfort (0,21
It is possible to eliminate offsets (residual deviations) that are harmful to controlling (Z~27) to the optimum vibration level.

Therefore, it is possible to control the damping force to follow the fluffy component of the target control force U, and at the same time achieve the optimum vibration level. Since the gain is sufficiently high for the required frequency, it has the advantage of improving the stability of the control system.

Moreover, the actuator means (■) for controlling the damping force fc is
Instead of using a return spring to respond to the force generated by a linear actuator, the displacement of the spool is fed back, so the spool can be moved with a small amount of electrical energy, and the force generated can be used effectively. It has improved responsiveness, can control fine vibrations with high frequencies, and does not require power sources such as hydraulic or pneumatic sources, thereby reducing the weight and space of piping.

This has the advantage of reducing costs.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the basic configuration of the present invention, Figure 2 is a block diagram showing the prior art, Figure 3 (a) is a diagram showing a two-degree-of-freedom pitch bounce model, and Figure 3 (b) is a roll diagram. Diagram showing bounce mode. FIGS. 4(a) and 4(b) are diagrams showing a two-degree-of-freedom roll bounce model. Figures 5 (a) and (b) are diagrams showing a two-degree-of-freedom pitch-roll model, Figures 6 (a) and (b) are diagrams showing a model of an automobile's gas-liquid fluid suspension, and Figure 7 is a diagram showing a book. FIG. 8(a) is a schematic configuration diagram of an automobile gas-liquid fluid suspension according to an embodiment of the present invention, and FIG. 8(b) is a sectional view of the actuator means. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. Fig. 10 is an operation flow diagram showing the operation flow of the embodiment shown in Fig. 9, and Fig. 11 shows control input, orifice opening, spool displacement,
FIG. 3 is a characteristic diagram showing the relationship between damping coefficients. ! ...State detection means, ■...Control means, ■. 1・
...State determination means, ■. 2... Target control force calculation means, ■2... Detection control force calculation means, ■,... Deviation calculation means, ■... Drive means, ■... Actuator means. Patent applicant Toyota Central Research Institute Co., Ltd. Toyota Motor Corporation Fig. 5 (a) (b) ront Fig. 6 (b) Fig. 7 Fig. 8 (0) (b) 55-'J-a.5s- x-960-Waterstone Figure 10

Claims (1)

[Scope of Claims] A state detection means for detecting a physical quantity that affects the characteristics of a suspension that supports a vehicle, and also detects a state quantity indicating the movement of the suspension and a state quantity indicating the movement of the vehicle, and an output of the state detection means. The pitch, roll,
a state determining means for calculating each vibration mode constituted by a combination of bounces, etc., and determining a dominant main vibration mode of the entire vehicle among the vibration modes; and a main vibration mode of the entire vehicle determined by the state determining means. target control force calculation means for calculating an optimal target control force based on the mode; detection control force calculation means for calculating a detection control force corresponding to the physical quantity detected by the state detection means; and the target control force and detection control a control means comprising a deviation calculation means for calculating a deviation from the control force; a drive means for power amplifying a deviation signal of both control forces which is an output of the control means; and an external force acting on the suspension based on the power amplified output. or actuator means for continuously variable control of suspension characteristics to equivalently generate a control force according to the deviation of the actual detected control force from the target control force taking into account external disturbances; By determining the dominant vibration mode of the entire vehicle from the degree of change in the state quantity or physical quantity of the suspension, and calculating the optimal target control force accordingly, it is possible to achieve optimal target control according to the main vibration mode of the entire vehicle. A variable damping force suspension control device that generates force and continuously optimally controls suspension characteristics.